Workers who maintain and upgrade Tube lines on London Underground are to strike for 72 hours next week in a dispute over pensions and benefits.
The Rail, Maritime and Transport union (RMT), which represents around 1,000 staff on the Tube Lines contracts, said its members will walk out at 4pm on Tuesday until the same time on Friday.
The staff work on the Piccadilly, Northern and Jubilee lines and provide a number of services, including emergency repairs, across the entire network.
The row is over union demands for all Tube Lines staff to be allowed to join the Transport for London pension scheme and receive the same travel concessions as those who work for London Underground.
RMT officials said the strike will have a "widespread" impact on Tube services across the network.
On Monday RMT General Secretary Bob Crow said the dispute was about "justice": “This is a massive mandate for action following a straightforward demand for parity with other Tube staff. This dispute is about justice and about ensuring that all groups of staff under the umbrella of London Underground receive the same rights and benefits.”
“We have gone through all the negotiating channels on both these issues but Tube Lines has refused to budge and have refused to engage in meaningful talks and that pig-headed approach has raised the temperature on the shop floor and is reflected in this result.